Support is requested for participation in the cooperative clinical trials of the Southeastern Cancer Study Group. Although the majority of studies are directed against hematological malignancies, especially Hodgkin's disease, acute leukemia in adults, chronic lymphocytic leukemia and lymphomas, emphasis is now shifting toward solid tumors. We deal primarily with chemotherapeutic drugs but are now incorporating the use of radiotherapy in comparison with chemotherapy or in combination with chemotherapy. Immunotherapeutic approaches are being explored. In addition to Group studies as described, ancillary studies at one or more institutions are encouraged, i.e. 1) Preliminary studies which may lead to data justifying a Group study; 2) Basic investigations directed toward elucidating mechanism of action or other aspects of treatment given in a Group protocol; 3) Studies directed at better methods of diagnosis or classification of diseases under study or better methods of evaluation of results. Emphasis is placed upon thorough planning, careful review of data and statistically sound evaluation of results. Important secondary benefits of these studies are the excellence of patient care and improved training of house officers and medical students.